Process of preparing steam cylinder oil



Patented June 22, 19 37 UNITED STATES PATENT OFFICE PROCESS OF PREPARING STEAM CYLINDER of California No Drawing.

8 Claims.

This invention relates to the treatment of lubricating oil to insure stability under conditions A of high temperatures and pressures in the presence of steam and has for a particular object the preparation of a lubricating oil especially adapted to function in the cylinders of steam engines.

In the manufacture of steam cylinder oils certain specifications must be strictly adhered to because of operating conditions peculiar to the uses of such oils.

Steam cylinder oils may not be supplied to the walls of the pistons and cylinders of the engine in many 'of the well-known forms of lubrication,

but are introduced to the cylinder with the steam In modern steam engine practice the temperature of the steam in the cylinder of the engine when closed by the piston goes as high as 500 F.

conditions it is highly important not only that a properdistribution of the oil is assured, but also that the stability of the oil is such as to resist decomposition, whereby undesirable deposits, such as coke, and the like, are eliminated. Oils which have a tendency to emulsify with steam are best suited for steam cylinder oils and heretofore it has been common practice to compound with a mineral oil a certain percentage of a fatty oil, such as tallow, which causes emulsification. Such fatty oil, or oils, usually represent up to 8% to 10% of the mineral oil, but in addition to being'costly, are decomposed at high tern.- 35 peratures which do not affect the mineral oil hydrocarbons, thus forming free fatty acids which attack metals under such temperature conditions. The problems of steam cylinder lubrication are thus inherently di-fleren't from the problems of 40 lubricating the cylinders of internal combustion engines, due to operating conditions at high temperatures and pressures in the presence onwater vapor, which factors require that the cylinders be preferentially wet with the oil rather than with- 45 the water.

For. this reason, high viscosity oils have been found best suited for steam cylinder lubrication and such oils should be processed for emulsiilcation with the steam used in order to provide the 50 desired preferential wetting of the cylinder. with under its corresponding pressure, and under such,

Application May 29, 1936, Serial may vary depending on whether a Pennsylvania oil or a western oil is used but the viscosity of a steam cylinder oil is generally greatly different from a transformer oil, or light lubricating oil used in internal combustion engines.

This invention provides a way of insuring the stability of steam cylinder oils while emulsifying the same under operating conditions, which is preferably accomplished in the following manner. As a base stock for steam cylinder oils it is preferred to select a lubricating oil of high viscosity which is composed mainly of saturated hydrocarbons, such oil, for example, being a heavy asphaltic base, or mixed base, oil, which is highly re- 1 fined by treatment with liquid sulphur dioxide,

' as in the well-known Edeleanu process, to remove unsaturated hydrocarbons, aromatics, etc. Such lubricating oil, thus treated, shows the greatest stability under high heat conditions, but, of course, a body of saturated hydrocarbons may also be prepared by extensive sulphuric acid treatment, or even distilled from certain stocks, such as Pennsylvania crudes.

To such stable lubricating oil is added a trace of a lime or magnesium soap of an organic acid, such, for example, as oleic acid, stearic acid, naphthenic acid, or sulphonic acid, the proportion of such added soap ranging in very small percentages of the oil, preferably from .01% to .1%. K a While the above-mentioned soaps are preferred, the use of minute quantities of other soaps is eifective to give emulsifying" properties to lubricating oils, the percentages being such that the amount of ash arising from their use as emulsifiers is generally too small to be determined analytically.

' This use results in a'steam cylinder oil of unimpaired stability which emulsifles sufficiently to get the desired distribution, the soaps being eas-c.

ily combined with the saturated hydrocarbons due to their oil solubility.

Likewise, a steam cylinder oil having the required emulsifying properties may be prepared from oils which result from the distillation of a suitable crude stock and which may be naturally composed mainly of saturated hydrocarbons. For instance, residual oils of Pennsylvania origin are found to contain organic acids in sufllcient quantities that when traces of oxides, or hydroxides, are added to the oil when heated, such oil develops the desired pronounced emulsifying properties.

A preferred amount of magnesium oxide, or lime, or other alkaline earth oxide, or hydroxide,

' or may be blended in amounts or from to 1 normally present in petroleum to a hydrocarbon I 20% with a body of a highly refined oil of high stability, such as the S02 treated oil previously described.

While it is unnecessary, the use of small amounts or an acidless fatty oil with the steam cylinder oils prepared as above describedhas sometimes a beneficial efiect in lowering the surface tension, but the quantity used, from 0% to 3%, is kept as low as possible and in any event is tar less than the amount normally used in compounding steam cylinder oils.

This application is a continuation in part of our co-pending application S; N. 92,615, filed Got. 31, 1930.

We claim:

'. 1. A process of preparing an emulsifiable oil suitable for use in the cylinders of steam engines which compriseszladding from 0.01% to 0.1% of an alkaline earth metal soap of an organic acid lubricating oil having a viscosity suitable ior use as a steam cylinder oil; said oil being substantially free from organic acids. 2. A process of preparing an emulsiiiable'oil suitable for use in the cylinders of steam engines which comprises: adding from 0.01% to 0.1% of an alkaline earth metal soap of an organic acid normally present in petroleum to a saturated hydrocarbon lubricating oil having a viscosity suitable for use as a steam cylinder oil; said oil being substantially free from organic acids.

3. A process of preparing an. emulsifiable oil suitable for use in the cylinders of steam engines which comprises: adding from 0.01% to 0.1% of an oil soluble alkaline earth metal soap of an organic acid normally present in petroleum to a hydrocarbon lubricating oil having a viscosity.

normally present in petroleum to-a hydrocarbon aoeatea lubricating oil having a viscosity suitable for use as a steam cylinder oil and being substantially free from organic acids; said percentage ranging upward from 0.01% to a percentage insumcient to deposit ash when said mixture is injected with direct steam into the cylinder of a steam engine.

5. A process of preparing an emulsifiable oil suitable for use in the cylinders of steam en- 'gines which comprises: mixing a percentage of calcium naphthenate to a hydrocarbon lubricating oil having a viscosity suitable for use as a steam cylinder oil and being substantially free from organic acids; said percentage ranging up- .ward from 0.01% to a percentage insufficient to deposit ash when said mixture is injected with direct steam into the cylinders of a steam engine.

6. A process of preparing an emuisifiable oil suitable for use in the cylinders of steam engines which comprises: mixing a percentage of magne'siumnaphthenate to a hydrocarbon lubricatin'g oil having a viscosity suitable for use as a steam cylinder oil and being substantially free from organic, acids; said percentage ranging upward from 0.01% to a percentage insumcient to deposit ash when said mixture is injected with direct steam into the cylinders of a steam engine.

'7. In the lubrication of the cylinders of steam engines, the improvement which comprises commingling with the steam supplied to such cylinders: a hydrocarbon lubricating oil substantially free of organic acids and containing upward of 0.01% of an alkalinevearth metal soap of organic acids normally present in petroleum sumcient to cause emulsification of said oil when introduced into said cylinders but insuficient to cause substantial formation of decomposition products at the temperature of such emulsificatipn.

8. In the lubrication of the cylinders of steam engines, the improvement which comprises commingling with the.steam supplied to such cylinders: a hydrocarbon lubricating oil substantially free of organic acids and containing from 0.01% to 0.1% of an alkaline earth metal soap of organic acids normally present in petroleum sum- ARTHUR LAZAR. JOSEPH v. cRENna. 

